Apparatus for centering the longitudinal axis of a log on a reference axis

ABSTRACT

Apparatus for centering the longitudinal axis of a log on a reference axis comprises two scanning or sensing devices which determine the horizontal and vertical deviation of the longitudinal axis from the reference axis and which sense the log in each case at two sensing points, and a device controllable by the sensing devices for aligning the log in the vertical and horizontal directions corresponding to the signals supplied by the sensing devices.

United States Patent [191 Ketteler [4 1 Sept. 2, 1975 APPARATUS FORCENTERING THE LONGITUDINAL AXIS OF A LOG ON A REFERENCE AXIS [75]Inventor: Otto Ketteler, Bad Iburg, Germany [73] Assignee: C. Keller u.Co., Laggenbeck,

Germany [22] Filed: Jan. 2, 1974 21 Appl. No.: 430,090

[30] Foreign Application Priority Data Feb. 8, 1973 Germany 2306214 [52]US. Cl 144/209 A; 82/2.5; 82/45; 356/ 167 [51] Int. Cl. B27L 5/02; B23B23/00 [58] Field of Search 82/2.5, 45; 356/167; 144/209 R, 209 A [56]References Cited UNITED STATES PATENTS 7/1968 Brookhyser et a1 82/45 X3,504,719 4/1970 82/45 X 3,664,395 5/1972 Reed... 144/209 A 3,712,7411/1973 Revert 356/167 X 3,746,065 7/1973 Mason 144/209 A X 3,752,2018/1973 I-Ieth 144/209 A FOREIGN PATENTS OR APPLICATIONS 1,913,965 9/1970Germany 144/209 A 1,913,964 9/1970 Germany 144/209 A PrimaryExaminer-Donald R. Schran Assistant Examiner-W. D. Bray [5 7] ABSTRACTApparatus for centering the longitudinal axis of a log on a referenceaxis comprises two scanning or sensing devices which determine thehorizontal and vertical deviation of the longitudinal axis from thereference axis and which sense the log in each case at two sensingpoints, and a device controllable by the sensing de vices for aligningthe log in the vertical and horizontal directions corresponding to thesignals supplied by the sensing devices.

15 Claims, 4 Drawing Figures AVAF/Af/AYAY w 8 PATENT SEF 2197s sum 1 or4 Fig.1

PATENTEB SEP 2 I975 SHEET 2 BF 4 W A y PATENTED SEP 2 I975 SHEET 3 0F 4.

APPARATUS FOR CENTERING THE LONGITUDINAL AXIS OF A LOG ON A REFERENCEAXIS An apparatus for centering the longitudinal axis of a log on areference axis is used in particular for centering logs or round woodpieces to be further processed in a veneer peeling machine. Thecentering apparatus is intended to determine the optimum centeringpoints for clamping the wood in the veneer peeling machine with respectto the natural curvature of the log.

In a known centering apparatus for timber the article whose longitudinalaxis is to be centered on a reference axis, i.e. in this case a lengthof round wood, is supported by a device which serves to align thearticle in the vertical and horizontal directions and which comprisessubstantially two spaced. independently actuable. vertical liftingdevices each comprising an element which supports the article at twopoints. Each vertical lifting device is supported in a carriage by whichsuch lifting devices can be displaced in a horizontal directiontransversely of the reference axis. The known centering apparatus alsocomprises within the region of each end of the article a sensing devicewhich scans or senses the article at two diametrically opposite sensingpoints (at the periphery). Each sensing device comprises two armsengaging round the article, such arms being pivotally mounted at acentral axis and connected together for joint pivotal movement via toothsegments; the substantially coplanar angled arms may be pivoted aboutthe middle axis of the central axis so that they can sense the articleon the one hand in the vertical direction and on the other in thehorizontal direction. Whereas the one sensing arm is made on the wholerigid. the leg of the other sensing arm coming into contact with thearticle is movable between two fixed end positions. To pivot and rotatethe arms several separate drive means are provided.

To center an article with this known apparatus the article is firstaligned in the vertical direction by setting the sensing arms of the twosensing device perpendicular to each other. the article then firstlybeing aligned in the vertical direction in accordance with the signalssupplied by the two sensing devices (which each control a liftingdevice). After this vertical alignment the sensing arms of the sensingdevices are pivoted about the central axis through 90 so that ahorizontal alignment may be effected, the signals now supplieddisplacing the vertical lifting devices on their carriages, thushorizontally aligning the article.

As is apparent from the foregoing description of the mode of operationof the known centering apparatus (firstly vertical alignment of thearticle and then horizontal alignment, after switching over the sensingdevices) the centering operation is extremely complicated and timeconsuming. Furthermore, the known centering apparatus involves aconsiderable amount of expenditure, both as regards the structure and asregards the production costs. The complicated construction also has thedisadvantage that the apparatus must be very carefully maintained toensure that in particular the sensing arms function satisfactorily.

The principal object of the invention is to provide a centeringapparatus especially adapted to center articles such as logs to bepeeled for veneer and which, in spite of a relatively simpleconstruction, permits rapid and reliable centering of such articles.

According to the invention this object is realized in that the twosensing points of each sensing device inelude a peripheral angle of lessthan and the device for alignment corresponding to the signals suppliedby the two sensing devices is simultaneously actuable in the sense of avertical and a horizontal alignment.

Where the sensing devices of centering apparatus according to theinvention approach the periphery of the article to be sensed and sucharticle is not aligned, one sensing point of at least one sensing devicewill detect the article and then supply a corresponding signal by whichthe device for aligning the article is then correspondingly movedhorizontally. Thereafter, the vertical movement of the aligning devicemay be continued until at least one sensing point again provides adetection signal. This again results in a corresponding horizontalmovement of the alignment device and thus in a further alignment orcentering of the article. These aligning operations are continued untilboth sensing points of the sensing devices detect the article. whichindicates that the longitudinal axis of the article is centered in thedesired manner on a reference axis.

The alignment operations described are effected very rapidly insuccession without appreciable delay and consequently rapid centering ofthe article is ensured.

The apparatus according to the invention may be of relatively simpleconstruction and the production costs of such an apparatus are thuscomparatively low. The simple structure of said apparatus also meansthat relatively little expenditure is involved in the maintenance.

An embodiment of the invention is illustrated in the accompanyingschematic drawings, wherein:

FIG. 1 is an elevational view of the centering apparatus; and

FIGS. 2-4 are sectional views along the line llIl of FIG. 1 illustratingthree different working positions when centering a piece of roundtimber.

The longitudinal axis A of a length of round timber I is to be centeredon a reference axis with respect to the natural curvature of the roundtimber in order to give the optimum centering points at the end faces ofthe timber so that, after centering, the timber can be clamped for afurther operation by a veneer peeling machine, for example.

In the disclosed embodiment the timber l to be centered is supplied by afeed means 2 to the working vicinity of the apparatus. This feed means 2may for example be two endless convcyor belts, chains or the likerunning adjacent and parallel to each other and made in the usualmanner.

Provided beneath the feed means 2 are two vertical adjusting or liftingdevices 4 which are accommodated in a pit 3 and which may beindependently operating hydraulic cylinder-piston means whose liftingrams 4a comprise at each of the upper ends a support prism 5 constructedas a two-point support element and comprising support faces 5a and 5b.The support faces 5a and 5b of each prism 5 are arranged substantiallysymmetrically to each other and form an included angle of less than 180so that they engage the timber 1 from below at two support points. Eachof the two vertical lifting devices 4 is articulately mounted, in thepresent case at the lower end, in such a manner that they can be pivotedabout a joint horizontally extending axis a lying parallel to thereference axis, thereby enabling adjustment of the supports transverselyof the latter axis.

For this pivotability each vertical lifting device 4 is articulatelyconnected in the region of its upper cylinder end to a horizontaladjusting device 6 which in turn is articulately mounted, at its otherend, to a wall 3a of the pit 3 (cf. FIGS. 2-4). These horizontaladjusting devices 6 may also be fluid-operated cylinder-piston means.

Each adjusting device 4 and 6 is supplied with operating fluid by meansof a pump P via electrically controlled valving V, V of known kindoperable to extend and retract the pistons of the respective devices.

The vertical lifting devices 4 (with their support prisms 5) and thehorizontal adjusting devices 6 represent the most important parts of anapparatus for aligning the timber l in a vertical and horizontaldirection.

Arranged fixedly adjacent the pit 3 and longitudinally of the feed means2 are two vertical supports or posts 7, 8 (on both sides of theconveying means). Disposed on each post 7, 8 is a carriage 9 and 10respectively which can be displaced on the associated post in thevertical direction. Rigidly secured to each carriage 9, 10 is asubstantially horizontally extending cantilever arm in verticalalignment with the reference axis. The two cantilever arms 11, 12 extendtowards each other and are in alignment.

Each cantilever arm 11, 12 carries a sensing device 13 and 14respectively which can be moved horizontally along the associated arm.For this purpose each arm 11, 12 is equipped with a screw spindle 15, 16which may be driven by an associated gear motor M and M respectively.The sensing devices 13, 14 are slidingly mounted on the arms 11, 12 byslide blocks 17, 18 which also include a corresponding connection to thespindles l5, 16.

The horizontal displaceability of the sensing devices 13, 14 enables thelatter to be set to the optimum longitudinal regions of the round timber1 to be measured. Regions within about 100 mm from the end faces of thearticle to be measured have been found to be favorable sensing regions.

As is further apparent in particular from FIGS. 2 to 4, each sensingdevice 13, 14 comprises two spreading arms 19, and 21, 22 respectivelywhich are made symmetrical with respect to each other and divergedownwardly substantially prismatically and in this embodiment are eachformed by two struts to provide greater twisting resistance.

Provided on each sensing device 13, 14 are two sensing members which ineach case determines a sensing point which senses the timber 1 at itsperiphery. In the disclosed embodiment the sensing members are each anelectrical switching photocell F arranged on a spreading arm (forexample 19, 20) and a cooperating light source S at the free end of theother spreading arm (for example 20, 19). In each sensing device 13, 14the light beams L directed from the light sources S to the associatedphotocells F intersect below the corresponding spreading arms in such amanner that the lower sections containing the two sensing points of eachlight beam include between them an angle a of less than 180. The lightsources may be suitably constructed and aligned mirrors S which aremounted at the free ends of the spreading arms 19, 20 and 21, 22 withthe aid of support plates 23, 24 and 25, 26, respectively.

The two sensing devices 13 and 14 operate independently of each otherand cooperate with the vertical lifting device 4 (including itshorizontal adjusting device 6) disposed on the same side, the sensingdevices controlling the lifting devices in the sense of a vertical andhorizontal alignment of the article to be centered, i.e. in this casethe timber l. The sensing devices 13, 14 and the associated lifting rams4a and their support prisms 5 are connected to each other in such amanner that they may be moved in opposite directions, i.e. when forexample the vertical lifting devices move an article to be centeredvertically upwardly the sensing devices 13, 14 move via their arms ll,12 and the carriages 9, 10 on the corresponding posts 7, 8 downwardly sothat the timber 1 may be scanned by the sensing members. To connect thelifting rams 4a with the carriages 9 and 10 roller chains, cables or thelike may be provided as indicated at 27 and 28, which are guided bymeans of corresponding rollers. To facilitate the displacing of the arms11 and 12 and their carriages 9 and 10 on the posts 7 and 8 balanceweights 31, 32 are provided on chains or the like 29, 30, the latteralso being led in suitable manner over guide rollers.

The photocells F of one sensing device are electrically coupled to thevalve V of the associated vertical lifting device 4 and to the valve Vof the related horizontal adjusting device 6 in such manner that, whenboth light beams L are uninterrupted, the piston 4a of the device 4 isdriven upwardly. When either light beam L is interrupted, upwardmovement of the piston ceases and, depending on which beam L isinterrupted, the associated adjusting device 6 will be either extendedor contracted. The other sensing device has its photcells F similarlycoupled to the valves of the other adjusting devices 4 and 6.

A centering operation will be described hereinafter with reference toFIGS. 2 to 4.

The timber 1 to be centered is conveyed by the feed means 2 to the pit 3and engaged by the support prisms 5 from below and lifted off the feedmeans 2. As particularly clearly apparent from FIGS. 2 to 4, thevertical lifting devices 4 are in their vertical positions in alignmentwith the posts 7 and 8 so that in this condition the support prisms 5are also symmetrical to the spreading arms 19, 20 and 21, 22respectively of the associated sensing devices 13, 14. When the verticallifting devices 4 or their support prisms 5 have raised the timber 1from the feed means 2 (cf. FIG. 3) they continue their vertical upwardmovement. Due to the connection between the sensing devices 13, 14 andthe associated support prisms 5 these elements are moved verticallytowards each other until at least one beam L of one sensing devicesenses the timber 1, whereupon the ray path from the correspondingsource S to the associated photocell F is interrupted or occupied. Theresulting signals actuate the corresponding horizontal jack or adjustingdevice 6 in such a manner that the vertical lifting device is pivotedabout its axis a and thus the timber 1 is adjusted horizontally. Afterthis adjustment operation the light beam path from the source S to thephotocell F is again free and consequently the vertical approach of thesensing devices 13, 14 to the timber 1 may be continued. As soon as atleast one of the beams is interrupted by the periphery of the timber 1the horizontal adjusting movement described above is repeated. Theseadjustment operations in the vertical and horizontal direction (inaccordance with the signals supplied by the sensing devices 13, 14) arerepeated until all of the light beam paths to the photocells F in thescanning devices 13 and 14 are occupied. The timber l is now scanned bythe sensing devices l3, 14 at two sensing points T and T spaced by aperipheral angle B with reference to the timer 1 of less than 180. Thatis, the moving points lie on an arc of less than 180. These sensingpoints T T are in the lower portions of the intersecting light beam L.The longitudinal axis A of the timber l is now exactly aligned on thereference axis. Using the optimum centering points determined in thismanner (at the two end faces of the round timber l) the timber may thenbe clamped in a veneer peeling machine for further processing. timberbeams In the centering operation described on the basis of the signalssupplied by the two sensing devices 13, 14 a vertical and horizontalalignment of the support prisms 5 (and of the lifting means carryingthem) on which the timber 1 rests is effected simultaneously. Since theaforementioned brief alignment operations may follow each other inpractice relatively rapidly, the apparatus according to the inventionpermits a very rapid centering of the timber 1.

The apparatus according to the invention is of relatively simpleconstruction, which also reduces production costs and makes maintenancesimple.

Various modifications of the centering apparatus described are of coursepossible within the scope of the invention, including embodimentssuitable for centering elongated articles other than the round timberlength for a veneer peeling machine referred to in the example. Forsensing the article to be centered, instead of the photocells otherfeeler members may be employed containing electrical limit switchesactuated for example via chains, cables or other flexible elements oncontact with the article; the chains, cables or the like would then besubstantially equivalent to the light beams of the photocells.

I claim:

1. Apparatus for centering the longitudinal axis of an article on areference axis comprising a pair of supports spaced along said referenceaxis for supporting an article with its longitudinal axis substantiallyhorizontal; means mounting each of said supports for independentvertical movement and for independent movement transversely of saidreference axis; a pair of article sensing devices; means mounting saidsensing devices in a position in which either of the latter is operableto sense an article supported by said supports; and adjusting meansresponsive to the operation of either one of said sensing devices toeffect individual adjustment of said supports vertically andtransversely of said reference axis.

2. Apparatus according to claim 1 wherein said supports comprise a pairof independent members each of which is pivotal about a pivot axisparallel to said reference axis.

3. Apparatus according to claim 2 wherein said adjusting means isoperable to rock said members about said pivot axis.

4. Apparatus according to claim 1 including means for effecting relativevertical movement of said supports and said sensing devices in adirection toward one another.

5. Apparatus according to claim 1 wherein said sensing devices definetwo sensing points located on an arc of less than 6. Apparatus forcentering the longitudinal axis of an elongate article on a referenceaxis comprising a pair of independent supports spaced from one anotheralong said axis a distance to support such article adjacent oppositeends of the latter; means mounting said supports for independentadjustment vertically and transversely of said reference axis; a pair ofsensing devices spaced from one another along said reference axis andeach of which defines two sensing points lying on opposite sides of saidreference axis; means mounting said sensing devices in a position inwhich each of said sensing points is operable to sense the presence ofan article on said supports; and a pair of independent adjusting meansconnected to each of said respective supports for adjusting the lattervertically and transversely of said reference axis, one of saidadjusting means being responsive to operation of either sensing point ofone of said sensing devices to adjust one of said supports verticallyand transversely of said reference axis and the other adjusting meansbeing responsive to operation of either sensing point of the other ofsaid sensing device to adjust the other support vertically andtransversely of said reference axis.

7. Apparatus according to claim 6 wherein said sens ing devices aremounted at a level above said supports, and including means foradjusting said sensing devices vertically.

8. Apparatus according to claim 7 wherein the means for adjusting saidsupports and said sensing devices effects simultaneous vertical movementof said supports and said devices in opposite directions.

9. Apparatus according to claim 6 wherein the mounting means for saidsensing devices includes horizontal arm means on which said devices aremovable horizontally.

10. Apparatus according to claim 9 wherein said arm means are insubstantial alignment with said reference axis.

11. Apparatus according to claim 6 wherein each of said sensing devicesincludes a pair of substantially prismatically open spreading armsconfronting said sup ports.

12. Apparatus according to claim 6 wherein each of said sensing devicesincludes electrical switching means.

13. Apparatus according to claim 6 wherein each of said sensing devicesincludes a pair of spreading arms extending on opposite sides of saidreference axis; a photocell carried by each of said arms; and a lightsource carried by each of said arms, the light source of one of saidarms being capable of establishing a first light beam to the photocellof the other of said arms, and the light source of the other of saidarms being capable of establishing a second light beam to the photocellof said one of said arms.

14. Apparatus according to claim 13 wherein said first and second lightbeams intersect.

15. Apparatus according to claim 13 wherein said arms extend alongdownwardly diverging lines forming an included angle therebetween ofless than 180.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,902,539 Dated September 2, 1975 Inventor(s$ OttO Ketteler It iscertified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

Column 5, line 3, change "timer" to -timber--.

Column 5, line 11, delete "timber" Column 5, line 12, delete "beams"Signed and fieale d this twenty-fifth Day of November 1975 [SEAL] A ttest.

RUTH C. MASON C. MARSHALL DANN ff Commissioner ofPalenrs and Trademarks

1. Apparatus for centering the longitudinal axis of an article on areference axis comprising a pair of supports spaced along said referenceaxis for supporting an article with its longitudinal axis substantiallyhorizontal; means mounting each of said supports for independentvertical movement and for independent movement transversely of saidreference axis; a pair of article sensing devices; means mounting saidsensing devices in a position in which either of the latter is operableto sense an article supported by said supports; and adjusting meansresponsive to the operation of either one of said sensing devices toeffect individual adjustment of said supports vertically andtransversely of said reference axis.
 2. Apparatus according to claim 1wherein said supports comprise a pair of independent members each ofwhich is pivotal about a pivot axis parallel to said reference axis. 3.Apparatus according to claim 2 wherein said adjusting means is operableto rock said members about said pivot axis.
 4. Apparatus according toclaim 1 including means for effecting relative vertical movement of saidsupports and said sensing devices in a direction toward one another. 5.Apparatus according to claim 1 wherein said sensing devices define twosensing points located on an arc of less than 180*.
 6. Apparatus forcentering the longitudinal axis of an elongate article on a referenceaxis comprising a pair of independent supports spaced from one anotheralong said axis a distance to support such article adjacent oppositeends of the latter; means mounting said supports for independentadjustment vertically and transversely of said reference axis; a pair ofsensing devices spaced from one another along said reference axis andeach of which defines two sensing points lying on opposite sides of saidreference axis; means mounting said sensing devices in a position inwhich each of said sensing points is operable to sense the presence ofan article on said supports; and a pair of independent adjusting meansconnected to each of said respective supports for adjusting the lattervertically and transversely of said reference axis, one of saidadjusting means being responsive to operation of either sensing point ofone of said sensing devices to adjust one of said supports verticallyand transversely of said reference axis and the other adjusting meansbeing responsive to operation of either sensing point of the other ofsaid sensing device to adjust the other support vertically andtransversely of said reference axis.
 7. Apparatus according to claim 6wherein said sensing devices are mounted at a level above said supports,and including means for adjusting said sensing devices vertically. 8.Apparatus according to claim 7 wherein the means for adjusting saidsupports and said sensing devices effects simultaneous vertical movementof sAid supports and said devices in opposite directions.
 9. Apparatusaccording to claim 6 wherein the mounting means for said sensing devicesincludes horizontal arm means on which said devices are movablehorizontally.
 10. Apparatus according to claim 9 wherein said arm meansare in substantial alignment with said reference axis.
 11. Apparatusaccording to claim 6 wherein each of said sensing devices includes apair of substantially prismatically open spreading arms confronting saidsupports.
 12. Apparatus according to claim 6 wherein each of saidsensing devices includes electrical switching means.
 13. Apparatusaccording to claim 6 wherein each of said sensing devices includes apair of spreading arms extending on opposite sides of said referenceaxis; a photocell carried by each of said arms; and a light sourcecarried by each of said arms, the light source of one of said arms beingcapable of establishing a first light beam to the photocell of the otherof said arms, and the light source of the other of said arms beingcapable of establishing a second light beam to the photocell of said oneof said arms.
 14. Apparatus according to claim 13 wherein said first andsecond light beams intersect.
 15. Apparatus according to claim 13wherein said arms extend along downwardly diverging lines forming anincluded angle therebetween of less than 180*.